The use of telecommunications networks and associated Network Access Devices (NADs) has increased dramatically over the last 20 years. We increasingly rely on network accessibility for voice, data and video communication, now integral to personal, government, business, education, health and safety communications.
In communication networks, a node is an active electronic device that is attached to a network, and is capable of sending, receiving, or forwarding information over a communications channel. A node is a connection point, either a redistribution point or a communication endpoint. In network theory, the term node may refer a point in a network topology where data links may intersect or branch.
A data link is the means of connecting one location to another for the purpose of transmitting and receiving digital information. It can also refer to a set of electronic assemblies, consisting of a transmitter and a receiver and the interconnecting data telecommunication circuit. Links are governed by a link protocol enabling digital data to be transferred from a data source to a data destination.
Network topology is the study of the arrangement or mapping of the network elements (links, nodes, etc.) of a network, comprised of the physical (real) and logical (virtual) interconnections between nodes. Local Area Networks (LANs) and Wide Area Networks (WANs) are examples of networks that exhibit both a physical topology and a logical topology. Any given node in a network will have one or more links to one or more other nodes in the network. Mapping of the links and nodes onto a graph results in a geometrical shape that determines the physical topology of the network. Similarly, the mapping of the flow of data between the nodes in the network determines the logical topology of the network. The physical and logical topologies may be identical in any particular network but they also may be different.
High performance and feature-rich communications in a “converged Internet Protocol” environment may in a single service include private intranet, voice, video, Internet, and business partner services. Rapid advances in optical communications technology and devices in terms of performance, reliability and cost over the last decade have enabled the deployment of optically routed Wavelength Division Multiplexing (WDM) networks which can be used to create high capacity nationwide and global broadband networks. In these networks, optical signals can flow end-to-end between users, many times without being converted to electrical signals at the network switches. They can offer large bandwidth, simple cross-connecting of high bit-rate streams, signal format and bit rate independent clear channels, equipment and operational savings, as well as maximum flexibility.
Optical networking provides the inter- and intra-transport capabilities for Access, Metropolitan and Global networks. These networks are composed of nodes and links, as described above. The links correspond to DWDM (Dense Wave Division Multiplexing) systems with multiple optical signals, also called Colors, Wavelengths or Channels. As used herein, color may be used to refer to wavelengths of visible, infrared or ultraviolet light. Multiplexing technology continues to evolve while current methods allow up to 80 discrete colors on a single pair of fibers. Nodes may be equipped with Optical Cross Connect devices where de-multiplexed optical signals are converted from the optical domain to the electronic domain, switched, converted back to the optical domain and multiplexed optically. This Optical-Electrical-Optical (OEO) function serves two purposes: switching and regeneration of the attenuated optical signals. In contrast Optical Switches operate optically so that the OEO function needed for regeneration of the signal and possibly for changing wavelength is performed before and/or after the optical switching function. Essentially, the optical switch serves as an automated optical patch panel. Also at a node, a Reconfigurable Optical Add/Drop Multiplexer (ROADM) in conjunction with transponders may be used to add/drop/switch channels optically.
Links equipped with DWDM systems require optical signal amplification every 100-150 kilometers and optical signal regeneration every 1000-1500 kilometers. With DWDM systems, all the optical signals can be amplified simultaneously, without de-multiplexing, while regeneration must be performed on the de-multiplexed optical signals individually.
It would therefore be desirable to develop a system, device and method to improve the assignment of colors (wavelengths) on individual optical routes. By utilizing an Integer Linear Programming model with the main objective of minimizing color change-over in mid route, the need for costly Optical Cross Connect devices known as Optical-Electrical-Optical devices can be significantly reduced. To the inventors' knowledge, no such system or method currently exists.